Electric heating unit



Patented Sept. 17, 1929 'UNITED STATES PATENT OFFICE HARRY A. FRIETCHEN,OF MANSFIELD, OHIO, ASSIGNOR TO WESTINGHOUSE ELEG- TRIC & MANUFACTURINGCOMPANY, A CORPOEATION OF PENNSYLVANIA ELECTEIC I-IEATING- UNITApplication filed November 6, 1328.

My invention relates to furnaces and more particularly to removableheating units for electric furnaces.

An object of my invention is to provide a relatively simple,light-weight and highly -efiicient heating unit for an electric-resistorfurnace.

Another object of my invention is to provide a heating unit that shallembody a skele- *ton frame so constituted that it will tend to enzage asupporting side wall of the furnace.

In practicing my invention, I provide a substantially plane skeletonmetal frame having a plurality of in-turned side-wall Channels in oneface thereof and having a bottom portion extending laterally from theplane of the frame. Refract-ory resistor-supporting members, ofsubstantially T-shape in lateral section, fit into the channels tosupport and space the relatively heavy preformed resistor conductor.

In the single sheet of drawings:

Figure l is a view, in front elevation, of a heating unit embodying myinvention;

Fig. 2 is a view of the heating unit, in vertical lateral section takenon the line II-II of Fig. 1;

Fig. 3 is a view, in vertical lateral section of a furnace in which islocated a heating unit embodying my invention;

Fig. 4 is a top plan view of a refractory resistor-supporting member;

' Fig.`5 is a View, in lateral section taken on 'the line V-V of Fig. l;

Fig. 6 is a top plan View of a resistorspacing member; and

Fig. 7 is a view, in lateral section taken on 'the line VIT-VII of Fig.6.

Referring more particularly to Fig. 1 of the drawings, a heating unit,designated generally by the numeral 11, embodies a skeleton 'metal frame12 which may be made of a suit'- 'able material to withstand thetemperatures 'to which it will be subjected when located in a furnacechamber. The front surface of the 'frame 12, which may be provided witha plurality of openings 13 to lighten the weight 'and reduce theheat-storage Capacity thereof, is provided with a plurality ofsubstantially 'horizontal ribs l& for stifening purposes.

Serial No. &17,637.

The rear face of the frame 12 is provided with a plurality of channels15 formed by pairs of ribs or side walls 16 and 17 the outer ends ofwhich are inturned toward each other, substantially as shown in Figs. 2and 3 of the drawings.

The bottom portion of the frame 12 has a base 18 which extends laterallyaway from the plane of the frame and towards that side thereof havingthe ribs 14. The bottom of the base 18 is provided with a slight upwardbevel, for a purpose to be hereinafter described in detail.

As shown in Figs. 2 and `3 of the drawings, I may provide three Channels15, each of which receves refractory members. The upper channel 15receives a plurality of refl-actory resistor-supporting members 19,shown in Figs. 4: and 5 of the drawings.

As there shown, the member 19 is of substantially T-shape in lateralsection, the head or enlarged portion thereof fitting into the channel.The forward portion is provided with a plurality of laterally-extendingrecesses 21 suitably spaced apart and with a l ongitudinally-extendinggroove 22 in one Iace.

The two lower Channels 15 receive resistor-spacing members 23, shownmore particularly in Figs. 6 and 7 of the drawings. The shape of themembers 23 is substantially the same as that of members 19 with theexception that they are provided with reccsses 24 which aresomewliatdeeper than the recesses 21. lVhile I have shown threeChannels, l do not desire to be limited to this number.

A resistor or heating element 25 comprises a plurality of loops havingsubstantially straight portions connected by suitable return-bentportions at the top and bottom thereof. The general shape of theperformed heating element is shown in Fig. 1 of the drawings and, whileI have there shown a resistor wire or rod, I may use a strip instead.The upper loops are supported by the members 19, the depending portionsfitting into the recesses 21. The lower part of thesubstantially-vertically extending straight portions are located in therecesses 24 and,

as stated above, I prefer to use a plurality tations shall be placedthereon as are imot such spacers, particularly so if the length of thedepending straight portions is relatively great and the resistanceconductor is relatively heavy.

A furnace structure 26 is illustrated generally in Fig. 3 of thedrawings and comprises a plurality of walls of refractory material soarranged as to enclose a furnace chamber 27. As the furnace structureitself constitutes no part of my invention, I do not deem it necessaryto illustrate or describe the same in further detail.

The heating unit ll embodying my invention is more particularly adaptedto be lo` cated closely adjacent to a vertically extending wall of thefurnace, the base portion 18 resting upon the bottom wall, theConstruction of the base portion being, as hereinbe` fore described suchas to cause the heating unit ll to lean against the cooperating wall,the outer faces of the members 19 and 23 operatively engaging the innersurface of the adjaeent wall. In order to insure that the heating unit11 shall remain in its normal operative position, I provide one or morehook members 28 of substantially L- shape and cooperating washers andnuts 29, the hook members extending through the wall and operativelyengaging the frame 12.

A support for material to be heat-treated, while located in the furnacechamber 27, may be a pedestal 31 which may be of any suitable or desiredhighly refractory material usually employed for such purposes.

lVhile I have shown only one heating unitlocated adjacent to one of theside walls of the furnace, I do not desire to be limited thus, as I mayuse heating units of this kind on or against any or all of thesubstantially vertically-extending walls of an electric furnace.

If it becomes necessary to remove one of the heating units 11, this canbe done very easily by loosening the nut or nuts 29 on the hook bolts 28and then pulling out the heating unit, it being understood, of course,that suitable terninal members (not shown) are provided and 'that thesehave been disengaged preparatory to removal of the heating unit.

The skeleton-frame Construction hereinbefore described provides aminimum heatstorage Capacity of the frame consistent with the necessarystrength and the resistor, which consists of a preformed relativelyheavy conductor, is supported and spaced thereby, and both lateral andlongitudinal movements of the individual loops or convolutionsisprevented by the refractory members.

Various modifications may be made in the device embodying my inventionwithout departing from the spirit and scope thereof and I desire,therefore, that only such limiposed by the prior art or are set forth inthe appended claims.

I claim as my invention:

1. In an electric furnace, a heating unit, comprising a skeleton metalframe having a plurality of Channels therein, the side walls of whichhave inturned ends, a refractory resistor-supporting member in theuppernost channel, a refractory resistor-spacing member in the lowermostchannel and a relatively heavy preformed resistor supported by theuppermost refractory member and extending through the refractory spacingmember,

2. In an electric furnace having a plurality of walls enclosing afurnace chamber, a heating unit extending along one of the walls andcomprising a skeleton metal frame having a plurality ofhorizontally-extending channels in one face, the side walls of eachhaving inturned ends, refractory electricinsulating members in eachchannel, the outer edges thereof operatively engaging the side wall, anda preformed resistor member of a relatively heavy conductor supported bythe upper refractory member and spaced apart by the lower refractorymember.

3. In an electric furnace having a pluralit-y of walls enclosing afurnace chamber, a heating unit extending along one of the side wallsand comprising a skeleton metal frame having a plurality of horizontallyextending Channels in one face, refractory members having a portionlocated in a channel and another portion extending away from the frameand operatively engaging the face of the wall, and a resistor membersupported by one of said refraetory members and having portions thereofspaced apart by other of said refractory members.

4. In an electric furnace having a plurality of walls enclosing afurnace chamber, a heating unit extending along one of the walls andcomprising a resistor conductor having a plurality of Suspended loops, arefractory support therefor, a refractory spacing member for the lowerpart of the resistor loops and a combined resistor-supporting andprotecting skeleton frame having interfitting engagement with therefractory members to support them and having also a base portionextending laterally away from the plane of the frame to cause it to leantoward the adjacent wall.

5. In an electric furnace having a plurality of walls enclosing afurnace chamber, a heating unit extending along one of the verticalwalls and comprising a resistor, refractoryresistor-supporting-and-spacing members, and a combinedresistor-supporting and protecting frame having a base portion extendinglaterally from the plane of the frame to cause it to lean toward theadjacent vertical wall.

6. In an electric furnace having a plurality of walls enclosing afurnace chamber, a. heating unit extending along one of the VerticalWalls and comprsing a resistor, refractoryresistor-supporting-and-spaeing members, and a combinedresistor-supportingand-proteeting frame having a base portion eXtendinglaterally from the plane of the frame to cause it to lean toward theadjacent Vertical Wall, and means extending through the adjaeentvertical Wall and engagng the upper edge of the rame for holding` t inproper operative position relatively thereto.

In testmony Whereof, I have hereunto subscrbed my name this 29 day ofOct. 1928.

HARRY A. FRIETCHEN.

